Method of improving tobacco



Patented Nov. 26, 1940 UNITED STATES PATENT OFFICE METHOD OF IMPROVING TOBACCO Hermann Baier,

Frankfort-on-the-Main, and

Paul Langenkamp, Darmstadt-Eberstadt, Germany, assignors to Deutsche Gold and Silber Scheideanstalt vormals Roessler, Frankfort-onthe-Main, Germany, a corporation of Germany No Drawing.

Application May 23, 1939, Serial No.

275,200. In Germany May 23, 1938 14 Claims.

- hydrogen peroxide.

It is already known that the fermentation of tobacco is promoted by treating it with a solution of hydrogen peroxide of approximately 3% concentration after the unfermented tobacco 'has been previously moistened so as to absorb approximately 45% of its weight of water.

It has also been proposed to bleach tobacco by spraying the tobacco with a solution of hydrogen peroxide of 5% concentration. This process produces excellent results with fermented tobacco, and very much improves the tobacco, particularly lightening the color of the relatively darker grades of tobacco. However, this treatment has not proven satisfactory for the treatment of unfermented tobacco leaves.

It is an object of our invention to provide an improved method for the treatment of unfermented tobacco whereby certain properties of the tobacco, particularly the color, taste, and aroma thereof, are substantially improved. A further object of the invention is the provision of an improved method for treating unfermented tobacco in order to improve the color and taste thereof, which method involves the use of a so-' lution of hydrogen peroxide of relatively high concentration. These and still further objects of the invention will be apparent from the ensuing disclosure of certain preferred embodie menth thereof.

We have found that the quality of unfermented tobacco can be very successfully improved by treating the tobacco with a solution of hydrogen peroxide if, during the treatment of the tobacco with the hydrogen peroxide solution of relatively high concentration, a maximum. of 20 liters and preferably from 14 to 18 liters of water are present per 100 kilograms of tobacco. By hydrogen peroxide solutions of relatively high concentration are meant solutions containing or more of hydrogen peroxide. After treatment, the tobacco is quickly dried at an elevated temperature,

for example one within the range 60 to 100 0.,

and finally subjected to steaming.

It is indeed surprising that a product of uniform appearance, the leaf structure of which is not unfavorably aflected, can be obtained in large scale operations employing hydrogen peroxide solutions of such high hydrogen peroxide concentration. This is only possible, as has been shown by experimental results, when the total quantity of water present is limited in accordance with the invention to a maximum of 20 liters per 100 kilograms of tobacco treated. Larger quantities of water, if present, result in undesirable discoloration of the tobacco.

Unfermented roof-ripened tobacco may be em- 5 ployed in carrying out the invention. It is then treated with a highly concentrated solution of hydrogen peroxide of 15%, 20%, or even higher hydrogen peroxide concentration. The application of the hydrogen peroxide solution to the 10 tobacco may be carried out in any convenient manner, and may be effected, for example, by spraying the tobacco with the solution by means of a nozzle system, the tobacco being held in mixing drums such as are generally utilized in 15 the tobacco industry. The materials of construction out of which the novel system and drums are constructed should be so selectedthat they tend to decompose the solution of hydrogen peroxide only to a very minimumamount. other words, the materials should not have an unfavorable catalytic efiect nor tend to influence unfavorably the rate of decomposition of hydrogen peroxide. It is frequently advantageous to have present substances of'alkalinereaction, particularly ammonia with the tobacco at the same time, or at substantially the same time, :that the solution of hydrogen peroxide is applied thereto.

The amount of hydrogen peroxide, and also the nature and amount of the particular alkali to be used may be readily determined for a particular grade of tobacco by a few preliminary experiments. These factors may obviously be varied appreciably, depending upon the final ef-'- fect desired, particularly the degree of lighteningof the tobacco desired.

The tobacco treated with the solution of hydrogen peroxide is quickly dried at an elevated temperature, for example one within the range 60 to 100 C., and is finally treated directly with steam. Drying and steaming maybe advantageously carried out in accordance with the methods customarily employed in so-called machine fermentation processes, e. g. utilizing a re-drying machine. the tobacco possesses the moisture content necessary for packing the tobacco in bales and for further processing. This may be, for example,

about 4% moisture content. The treatment with steam also serves to decompose any residual hydrogen peroxide present in or on the tobacco.

A further improvement may be carried out in accordance with this invention by subjecting the tobacco, treated with hydrogen peroxide, before the drying and, steaming treatment described 58 As a result of the steaming treatment,

' above, to a storage treatment in containers or in piled-batches. The duration of the storage periodlmay be varied within wide limits, depending upon the particular tobacco being treated and the character ofthe results desired. Normally a period ofone-half to three hours gives excellent results. During this storage period a fermentation-like reaction takes place with spontaneous evolution of heat. The tobacco is very much improved in quality as a result of this reaction.

The present method is especially applicable for treating the coarser, ranker, and less valuable grades of tobacco for the purpose of rendering them lighter, milder, and more agreeable in taste and flavor. The method also results in lessening, to a substantial degree, the nicotine content oi the tobacco, especially when the tobacco being treated is of relatively high nicotine content. The appearance of the tobacco is also greatly improved as a result of the marked lightening in color which results from the treatment.

As an example of our improved method the following may be given:

Example ide 11 Water 8 Aqueous ammonia of specific gravity 0.91 1

The tobacco is then piled in heaps, or is stored in containers, and thenallowed to stand for onehalf hour. Heat is spontaneously developed in the tobacco. After the storage period, the tobacco is then dried ina re-drying machine at a temperature of about 60 to 80 0., and is finally subjected to steaming.

It is apparent that many widely diflerent modifications of our invention may be utilized, which modifications will not depart from the spirit or scope of that invention as herein'described. Accordingly, our invention is not to be restricted to the preferred details or modifications given merely as illustrative, except as required by. the prior art and appended claims.

We'claim:

l. A method of improving tobacco which comprises treating unfermented tobacco in the presence of an alkaline agent with a highly concentrated solution of hydrogen peroxide containing hydrogen peroxide in amount at least 15% by volume, there being present duringsaid treatment an amount of water not exceeding 20 liters per 100 kilograms of tobacco being treated.

2. A method of improving tobacco which comprises treating unfermented tobacco in the presence of ammonia with a highly concentrated solution of hydrogen peroxide containing hydrogen peroxide in amount at least 15% by volume, there being present during said treatment anamount of water not exceeding 20 liters per 100' kilograms of tobacco being treated.

3. A method of improving tobacco which comprises treating unferl'nented tobacco with a highly concentrated ammoniacal solution of hydrogen peroxide containing hydrogen peroxide in amount at least 15% by volume, there being present during said treatment an amount of water not exceeding 20 liters per 100 kilograms of tobacco be-. ing treated.

4. A method of improving toboacco which comprises treating unfermented tobacco with a solution of hydrogen peroxide containing at least,15% by volume of hydrogen peroxide, there being present during said treatment an amount of water not exceeding 20 liters per 100 kilograms of tobacco being treated. I

5. A method of improving tobacco which comprises treating unfermented tobacco with a solution of hydrogen peroxide of relatively high concentration containing at least 15% by volume of hydrogen peroxide, there being present during said treatment an amount'of water falling within the range 14 to 18 liters of water per 100-kilograms of tobacco being treated.

6. A process as described in claim 4, whereinthe tobacco, at the conclusion of the hydrogen peroxide treatment, is dried and then steamed.

7. A process for improving tobacco which comprises treating unfermented tobacco with a highly concentrated solution of hydrogen peroxide containing at least 15% by volume of hydrogen peroxide, there being present during said treatment an alkaline substance, the amount of water present in contact with said tobacco during said treatment falling within the range 14. to 18 liters of water per 100 kilograms of tobacco.

8. A process as described in claim 7 wherein the tobacco, at the conclusion of the treatment with a solution of hydrogen peroxide, is dried and then steamed.

9. A method of improving tobacco whichcomprises treating unfermented tobacco with a highly concentrated solution of hydrogen peroxide containing at least 15% by volume of hydrogen peroxide, there being present during said treatment an amount of water not exceeding 20 liters per 100 kilograms of tobacco being treated, storing said tobacco, drying said tobacco, and finally contacting said tobacco with steam.

' 10. A process as described in claim 9 wherein the tobacco is stored in piled heaps prior to drying.

11. A method of improving tobacco which com-' prises treating unfermented tobacco with a solution of hydrogen peroxide containing at least 15% by volume of hydrogen peroxide, there being present during said treatment an alkaline substance, the quantity of water present during said treatment being restricted so as not to exceed 20 liters of water per 100 kilograms of tobacco, storing said tobacco at the conclusion of said treatment with hydrogen peroxide, drying said tobacco, and finally steaming said tobacco.

12. A process as described in claim 11 wherein the alkaline agent is ammonia.

13. A process as described in claim 11 wherein the amount of water present; per 100 kilograms of tobacco being treated,- is restricted to an amount within the range 14 to 18 liters.

14. A process as described in claim 11 wherein the toboacco is dried and steamed in a re-drying machine.

. HERMANN BAIER.

PAUL LANGEN'KAMP. 

